1. Field of the Invention
The present invention relates to a process for producing bisaminomethyicyclohexane as a useful raw material for polyamide resin and epoxy resin.
It is known that polyamides prepared from bisaminomethylcyclohexane (which will be hereinafter referred to as BAC) and an organic dibasic acid such as adipic acid or sebacic acid are materials having various distinguished properties. It is also known that polyurethane prepared from BAC as a raw material is elastic fibers, moldings or films having a very distinguished light resistance, and recently it has been regarded particularly as a hardening material for epoxy resin.
2. Prior Art
BAC has three isomers, i.e. 1,2-isomer, 1,3-isomer and 1,4-isomer, depending on the location of the aminomethyl groups. Heretofore, BAC has been commercially produced by hydrogenating the nitrile group of an aromatic dinitrile such as phthalonitrile, isophthalonitrile or terephthalonitrile, thereby forming a xylylenediamine, and then hydrogenating the xylylenediamine, thereby forming the corresponding BAC.
In the production of xylylenediamine by hydrogenation of an aromatic dinitrile, a Raney type catalyst such as Raney nickel or Raney cobalt, or a stabilized nickel catalyst, or such a catalyst as a platinum or rhodium catalyst is used, and various attempts have been so far made to increase the yield and the catalyst Life. For Example, Japanese Patent Application Kokai (Laid-open) No. 54-41804 discloses hydrogenation reaction in a solvent mixture of a lower alcohol and a cyclic hydrocarbon with a Raney nickel to prevent formation of secondary and tertiary amines. Japanese Patent Application Kokai (Laid-open) No. 56-63944 discloses hydrogenation of an aromatic nitrile in the presence of carbon dioxide with a palladium catalyst.
In the hydrogenation of xylylenediamine, various catalysts have been so far used. For example, Japanese Patent Application Kokai (Laid-open) No. 48-32845 discloses the use of a modified reduced cobalt catalyst and Japanese Patent Application Kokai (Laid-open) No. 50-126638 discloses the use of a ruthenium catalyst supported on an inert inorganic material. In order to increase the yield of BAC in the hydrogenation of xylylenedianine, Japanese Patent Publication No. 51-7659 discloses the use of liquid ammonia as a reaction solvent, and Japanese Patent Application Kokai (Laid-open) No. 54-16452 and U.S. Pat. No. 4,181,680 disclose the use of water as a solvent.
In the above-mentioned two-stage production of BAC, which comprises a first reaction stage of producing xylylenediamine from an aromatic dinitrile and a second reaction stage of hydrogenating the xylylenediamine to produce BAC, a reactor and steps for separating and purifying the reaction product are required for each reaction stage, and thus the one-stage direct production of BAC from the aromatic dinitrile, which combines these two-stage reactions, has been desired owing to its very high commercial significance. In this connection, U.S. Pat. No. 3,998,881 discloses the use of a solvent mixture of a specific organic compound and liquid ammonia with supported rhodium metal as a catalyst and U.S. Pat. No. 4,070,399 discloses the use of a catalyst of both ruthenium and palladium supported on an oxide carrier.
The one-stage direct production of BAC by simultaneous hydrogenation of the nitrile groups and the aromatic nucleus of a corresponding aromatic dinitrile is very advantageous, but its commercial process has not been established. That is, the rhodium used as a catalyst in U.S. Pat. No. 3,998,881 is a very expensive metal, which is not so resourceful. In the catalyst of both ruthenium and palladium supported on the oxide carrier for use in the one-stage production of 1,4-BAC from terephthalonitrile disclosed in U.S. Pat. No. 4,070,399, expensive palladium is used, and deterioration of the catalyst is considerable.
The difficulty of producing BAC from a corresponding aromatic dinitrile in one stage is due to the fact that the effective catalyst for producing an aromatic diamine from an aromatic dinitrile is not always effective for hydrogenating the aromatic nucleus of the aromatic diamine.